1. Field of the Invention
The present invention relates to a wiring structure in a semiconductor device and to a method of making the same and, more particularly, to a wiring structure in a semiconductor device having a gate electrode and a conductive region adjacent to the gate electrode for connecting a wiring layer formed on an upper portion of the semiconductor device and the conductive region and a method of making the same.
2. Description of the Related Art
FIG. 2 of the accompanying drawings shows a conventional wiring structure in a semiconductor device having a gate electrode formed on a silicon substrate, a wiring layer formed on the gate electrode with an insulating film between them and a contact hole through which the wiring layer is connected to the gate electrode. As shown in FIG. 2, a metal layer 22 is formed on an upper surface of a silicon substrate 21 at its predetermined position with a gate insulating film 32 disposed therebetween, and a silicon dioxide film layer 23 is laminated on the upper surface of the metal layer 22 as an insulating layer. A side wall 24 made of a silicon dioxide film is formed so as to cover each of side surfaces (left and right side surfaces in FIG. 2) of a lamination of the metal layer 22 and the silicon dioxide film layer 23 forming a gate electrode 25. Source-drain diffusion regions 30 are formed on the silicon substrate 21 at both sides of its portion on which the metal layer 22 of the gate electrode 25 is formed.
A silicon dioxide film layer 26 is formed so as to cover the upper surface of the silicon substrate 21 and the gate electrode 25. A contact hole 27 is formed by removing a part of the silicon dioxide film layer 26 by a photo-lithography technique. A wiring layer 28 is laminated so as to cover the inner surface of the contact hole 27 and the upper surface of the silicon dioxide film layer 26, and a contact part 29 is formed in the contact hole 27 for connection between the wiring layer 28 and the source-drain diffusion region 30.
However, as the size of the semiconductor device becomes greatly smaller, a spacing between the gate electrode 25 and the contact part 29 may be reduced so that the contact part 29 and the gate electrode 25 overlap with each other as shown in FIG. 2. Such structure involves a problem in that when the silicon dioxide film layer 26 is removed in order to form the contact hole 27, the gate electrode 25 may be exposed and the silicon dioxide film layer 23 may be partly removed, resulting in a short-circuit between the gate electrode 25 and the contact part 29 of the wiring layer 28.